Alkyl polychlorobenzyl ethers



nited States Company, North Adams, Mass., a corporation of MassachusettsNo Drawing. Application August7, 1951,.

Serial No. 240,800 a Claims. (Cl. 260-611) This invention relates to ancw'group of halogenated ethers. More particularly it refers to certaindialkyl ethers in which one of the alkyl groups is substituted with ahalogenated aromatic nucleus. This application is a continuation in partof our copending, application, Serial No. 12,138, filed February 28,1948, now U. S; Patent No. 2,564,214 granted August 14, 1951.

It is an object of this invention to produce new and useful compoundspossessing high boiling points and unusual chemical stability. A furtherobject is to produce valuable polar dielectric compositions. Anotherobject is to provide new and useful, flame-resistant, pentachlorobenzylalkyl ethers. Additional objects will become apparent from aconsideration of the following de-' scription and claims.

The compounds of our invention conform to the general formula:

in which R represents a bivalent, saturated, aliphatic hydrocarbonradical, R represents a monovalent. saturated, aliphatic, hydrocarbonradical, and n represents an integer from 1 to 2.

In a more limited sense the invention is concerned with compoundsconforming to the general-formula:

wagon) Clo-n. V

in which R and n have the same significance as' above.

Still more specifically the invention pertains to compounds conformingto the general formula:

in which R represents an alkyl group.

The preferred compounds of the invention, which conform to the lastformula given above, are pentachlorobenzyl alkyl ethers. Amongthepreferred' alkyl ethers of this type are:

Pentachlorobenzyl methyl ether Pen-tachlorobenzyl ethyletherPentachl'orobenzyl n-p'ropyl ether Pentachlorobenzyl isoprop'yletherPentachlorobenzyl butyl ether Pentachlorobenzyl amyl ether form to thefirst general formula, when R represents a bivalent, saturated,aliphatic hydrocarbon radical con- Patented Feb. 22, 1955 P CC tainingmore than one carbon atom, are of considerable interest. Among suchcompounds there may be mentioned the following:

Our new compounds may readily be prepared by reacting a halogenoalkyl'polychlorobenzene with an alkali metal alkoxide of an alcohol.Alternatively, they may be prepared by reacting a hydroxyalkylpolychlorobenzene with an aliphatic halide. The polychlorobenzenes usedwill contain either one or two halogenoalkyl or hydroxyalkyl groupsattached to the benzene nucleus, the remaining hydrogens on the ring.being substituted by chlorine. The halogenoalkyl groups preferablycontain a single chlorine or bromine substituent which combines with thealkali-metal of the alcoholate in the first mentioned. process.

The alcohol and aliphatic halides employed in the foregoing processesare preferably monovalent and saturated. Suitable alcohols for use inthe first mentioned process include the methyl, propyl-, 2-butenyl-,amyl-, pentenyl-, benzyl-,v etc. alcohols. Aliphatic halides that may beemployed in the second process include the ethyl'-, propenyl-, butyl-,etc. chlorides and bromides.

In the following examples, given for purposes of illustration, the firstmentioned process is used. Obviously, in most cases the second processcould be substituted with substantially equivalent results.

EXAMPLE 1 Preparation of penmchlorobenzylchloria'e 1065 gms. ofpentachlorotoluene were heated to its melting point, and chlorine wasintroduced, until the gain in weight was 137 gms. The crude reactionmixture was poured while hot into a distilling flask and. fractionatedat 0.27 mm. to yield a forerun, B. P. 120-132" C., weighing 70 gms. andthe main fraction, B. P. 134-136" C.,

H, and 1.98%.

weighing 1063 gms. This main fraction melted at-72--95 C.Crystallization from a 50-50 benzene alcohol mixture gave 796 gms.melting at 99-102 C.,representing a 66.5% yield ofpentachlorobenzylchloride; 4

EXAMPLE r1 Preparation 0 pentaehloroben-zyl methyl ether A mixture of14.9 gms. of pentachlorobenzylchloride, produced as described in ExampleI, 10 gms. of sodium hydroxide and 100 cc. of methanol was refluxed forten hours and then poured into water. The crude product was filtered anddried. It weighed 14 gms. and melted at 97-110 C. Crystallization fromethyl alcohol gave 9.5 gms., melting at 100-102 C. A sample crystallizedfor analysis two additional times from ethyl alcohol and once fromacetone melted at l07.5-108.5 C.

Calculated for CsHsOCls: C='32.60%, H=l.70%. Found by analysis: C=32.30and 32.12%, H=1.49 and 1.70%.

EXAMPLE III Preparation of pentachlorobenzyl ethyl ether A mixture of14.9 gms. pentachlorobenzylchloride, produced as described in Example I,10 gms. of sodium hydroxide and 100 cc. ethanol was refluxed for twohours and Water was then added. On cooling a solid precipitated. Thiswas filtered and crystallizedfrom 95% ethanol to yield 12 gms. of theether melting at 62-65" C. A sample crystallized for analysis four timesfrom 95% ethanol melted at 65-66 C.

Calculated for Cid-C151: -C=-35.l.0%, H=2.29%.

Found by analysis: C=35.40-and 35.18%, H=2.12

EXAMPLE 1v Preparation of pentachlorobenzyl propyl ether Sodiumpropoxide was prepared by adding 4.14 gms. sodium to 225 cc. n-propanol.44.8 gms. pentachlorobenzylchloride, produced as described in Example I,were added, and the mixture was refluxed for four hours and then pouredinto water. The organic material was extracted with chloroform. Thechloroform extract was. dried and distilled to yield 34 gms. (70%) ofthe desired ether, boiling at 131 C. at 0.4 mm. On standing, the ethercrystallized, melting at 34-37 C. A sample crys-' tallized for analysisfour times from 95% ethanol melted at 4344 C.

Calculated for C10H9OC152 C=37.24%, H=2.80%.

Found by analysis: C=37.72 and 37.96%, H=3.0l

and 2.78%.

EXAMPLE V Preparation of pentachlorophenyl-n-butyl etherSodium-n-butoxide was prepared by adding 13.8 gms. of sodium to 750 cc.n-butanol. 149.4 gms. of p'enta chlorobenzylchloride, prepared asdescribed in Example" I, were added, and the mixture was refluxed fortwelve hours. Water was then added. The butanol layer was separated,washed with saturated sodium chloride solution, dried over magnesiumsulfate, filtered and distilled yielding 112 gms. of the ether, boilingat 138-139 C. at 0.4 mm. A small sample redistilled for analysis had aB. P. of l38139.5 C. at 0.3 mm. and an index of refraction (n of 1.5612.The ether is liquid at room temperature.

EXAMPLE VI Preparation of 1,2-bis (bromomethyl)-3,4,5,6-tetrachlr0-benzene with slightly lower melting points.

, 4 hereinbefore given, is CH(CH3)- and ----CH2CH2--.

' 'Alpha-bromoethyl pentachlorobenzene may be refluxed with KOH andethanol to give l-pentachlorophenyl-lethoxyethane, M. P. 88-89 C.(Calculated for C1oHaCl5O: H='2.80, found H=2.72%.) Beta-chloroethylpentachlorobenzene may be refluxed with KOH and ethanol to give1-pentachlorophenyl-2-ethoxy-ethane, M. P. 8688 C. In each of thesereactions, a large amount of pentachlorostyrene was obtained bydehydrohalogenation of the side chain.

The compounds of the invention are of utility in a wide variety offields; Perhaps because chlorine and hydrogen atoms are not located onthe same or adjacent carbon atoms, our new materials exhibit unusualchemical and electrical stability. The stability is particularlypronounced, when compared with chlorinated diphenyl oxide and other,known halogenated aryl ethers.

Our new compounds are particularly desirable for ele'ctricalapplications. They possess relatively highdielectric constants, due totheir molecular structure. The boiling points are high, and theresistance to flammation is exceptional. The butyl ether described inExample V, and the bis-propoxymethyl compound described in Example VIIare both liquid at room temperature, and are es- The first crop amountedto 290 gms., M. P. 114- 117 C. Three other crops yielded a total of 92gms.

201 gms. of the l,2-bis(bromomethyl)-3,4,5,6-tetrachlorobenzene,produced as described in Example VI, were added to a solution of sodiumn-propoxide made from 27.6 gms. of sodium and 750 cc. of n-propanol.

pecially suitable as liquid dielectric impregnants for electricalcapacitors. The butyl ether possesses a dielectric constant in excess of5 at 60 cycles A. C.

The high chlorine content of the compounds results in theirapplicability where resistance to flame is a determining factor. Thecompounds and mixtures thereof are useful as heat-transfer mediums, asmodifiers for increasing the flash point of oils, finishes and the like,as transformer fluids and, for certain applications, as lubricatingmediums.

The polar nature and other features of the compounds described hereinpermit their use as plasticizers for resinous materials. Thepolyvinylhalides in particular, may be modified by incorporationtherewith of the halo ethers of the'invention. The chlorine content ofthese ethers results in satisfactory compatibility, and the flameresistance of the resin may be increased by such modification.

It is contemplated that the monovalent, aliphatic hydrocarbon radical Rin the first two general formulae may be further substituted for specialapplications, for example, where electrical stability is not animportant factor.

As many widely different embodiments of this invention may be madewithout departing from the spirit and scope hereof, it is to beunderstood that the invention is not limited to the specific embodimentshereof except as defined in the appended claims.

What we claim is:

1. A compound conforming to the formula:

C1 Cl C] CHQOR wherein R represents an alkyl group.

mixture was refluxed over night, water added and the organic layerseparated and washed with saturated sodium chloride. The organic layerwas then dried with magnesium sulfate and filtered. The excess propanolwas distilled off at atmospheric pressure and the organic residuefractionated at reduced pressure. fraction boiling at l48155 C. at0.25-0.6 mm. was the product.

Following the procedures outlined above, particularly that given inExample III, it has been possible to produce ethers wherein thebivalent, saturated aliphatic hydrocarbon radical R, appearing in thefirst general formula A 157 gm. 5??

2. Pentachlorobenzyl methyl ether. 3. Pentachlorobenzyl ethyl ether. 4.Pentachlorobenzyl propyl ether. 5. Pentachlorobenzyl butyl ether.

43 (1910), page 1837.

1. A COMPOUND CONFORMING TO THE FORMULA: